A portable audio communication device, such as a portable radio cellular telephone or the like, typically includes a speaker and a microphone. For radios providing full duplex communication, an earpiece enclosure may be utilized to minimize acoustic coupling to the microphone. However, the size of such an enclosure is limited by the size of the portable radio. Today's compact size portable devices do not provide sufficient space for an earpiece enclosure sufficiently large enough to faithfully reproduce an optimum low audio frequency response. In order to improve the low audio frequency response, acoustical leak ports are often used that lead to the earpiece enclosure. While the audio leak ports reduce the acoustical effect of the small enclosure, the audio leak ports can also cause water intrusion problems. Blocking the leak ports to prevent water intrusion can again cause a poor low audio frequency response.
Removal of the enclosure is not an option as this causes the audio signal to travel from the rear of the earpiece to the microphone thereby degrading the acoustic echo loss (AEL) performance. Poor acoustic echo loss causes conversation difficulties in full duplex calls.
Thus, the issues of echo suppression, fluid intrusion and low audio frequency response are all critical to the design of the acoustic porting of a portable full duplex communication device.
Accordingly, there is a need for a portable full duplex communication device with improved acoustic porting.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.